A Retrospective Analysis of Mortality Due to Pneumonia and Renal Disease in a Midwestern Patient Population

Background: The impact of pneumonia (PNA) with concomitant renal disease (RD) has not been fully investigated in a United States Midwestern patient population, despite the morbidity and mortality associated with such diseases.

Materials and methods: A retrospective cohort study was performed on International Classification of Diseases, 10^th Revision (ICD-10) data from a hospital system located in Southwest Missouri. Data was acquired from patients admitted between January 2019 and December 2021. Patients were separated into five groups (disease categories): acute kidney injury (AKI), chronic kidney disease (CKD), PNA, AKI with PNA, and CKD with PNA. The data were analyzed, and subset analysis was performed utilizing two-sample proportion tests (Wald test) to compare mortality rates. Informed consent was not needed due to the retrospective nature of the study.

Results: The mortality rate of patients with PNA with AKI and PNA with CKD was 36.08% (32.87% to 39.28%, 95% CI) and 24.97% (21.93% to 28.00%, 95% CI), respectively, revealing a significant increase in mortality for thosediagnosed with PNA and AKI -higher than any other disease category. For reference, PNA without (w/o) RD, CKD w/o PNA, and AKI w/o PNA had much lower mortality rates at 9.45%, 7.87% and 12.19%, respectively, with AKI w/o PNA having a 2.63% to 6.00% higher (p<0.0001) and 0.99% to 4.49% higher (p=0.0020), mortality alone than CKD w/o PNA or PNA w/o RD, respectively.

Discussion and conclusion: Mortality associated with RD and PNA was examined in a predominantly rural, relatively poor, Midwestern patient population presenting to a tertiary center with the key finding that the presence of AKI correlates with a much greater mortality rate in both patients with and without PNA. Looking forward, future studies may include a broader population base(including urban, suburban, and rural areas), allowing not only for more statistical power but also a broader assessment of the population.Such knowledge is invaluable as we continue to prioritize healthcare resources for critically ill patients suffering from RD and PNA in different settings.